Stair climbing wheelchair



April 15, 1969 B. M. BRADLEY STAIR CLIMBING WHEELCHAIR Sheet Z of 5 Filed March 31, 1966 A QH HH Ill I INVENTOR ATTORNEY STAIR CLIMBING WHEELCHAIR Filed March 51, 1966 INVENTOR ATTORNEY Sheet 4 ,z w I a .Mul EEEEEEEC ucccccli Z. 3 5 M y 6 7 April 15, 1969 a. M. BRADLEY 3,438,641

STAIR CLIMBING WHEELCHAIR Filed March 31, 1966 Sheet 3 of 5 INVENTOR STAIR CLIMBING WHEELCHAIR Filed March 51, 1966 Sheet INVENTOR Even/040M560 M 324945) A ORNEY April 15, 1969 B. M. BRADLEY STAIR CLIMBING WHEELCHAIR Sheet Filed March 31, 1966 VENTOR fl/frwzawau M 5/7/7045? BY W A ORNEY United States Patent 3,438,641 STAIR CLIMBING WHEELCHAIR Bartholomew M. Bradley, 378 Forest St, Kearny, NJ. 07032 Filed Mar. 31, 1966, Ser. No. 539,100 Int. Cl. B621) /02, 9/02; B6211 57/02 U5. Cl. 280-528 7 Claims ABSTRACT OF THE DISCLOSURE A motorized, self-propelled wheelchair adapted to ascend and descend stairs, has three pairs of driving wheels on each side, each set of wheels and the corresponding set of wheels on the opposite side of the chair are adapted to rest on the tread of the same stair while the other sets of wheels are on lower or higher stairs as the case may be. Mechanism is provided for raising or lowering corresponding sets of driving wheels together as necessary to negotiate stairs as the chair moves forward.

This invention relates to wheelchairs having stair climbing characteristics.

A principal object is to provide an improved stair claimbing wheelchair that duplicates the retractive leg movements of a person when ascending and descending a stairway, and wherein there is action of displacing steps in sequence.

Other objects are to provide a stair climbing wheelchair that is relatively simple in design, rugged in construction easy to use and efiicient in operation.

These and other objects will be readily apparent upon a study of the following specification and the accompanying drawing wherein:

FIGURE 1 is a fragmentary front perspective view of the invention,

FIGURE 2 is a fragmentary perspective view of the mechanism on one side of the chair,

FIGURE 3 is a similar view showing additional structure not included in FIGURE 2,

FIGURE 4 is an enlarged perspective view of part of the mechanism shown in FIGURE 2,

FIGURE 5 is a cross sectional view taken on line 5-5 of FIGURE 4,

FIGURE 6 is a cross sectional view taken on line 6--6 of FIGURE 4,

FIGURE 7 is a diagrammatical side elevation indicating an inclination position of the chair,

FIGURE 8 is another diagrammatical side elevation indicating relation motion thereof, and

FIGURE 9 is a side elevation view of a locking device.

Referring now to the drawing in detail the numeral 10 represents a stair climbing wheelchair according to the present invention wherein there is a seat 11, a back rest 12, side arm rests 13, telescopic legs 14, and a foot rest providing a support for a patient in a seated position.

The chair further incorporates a drive mechanism for propelling the chair up or down a stairway or along a level floor. The drive mechanism includes a plurality of drive units on each side of the chair, driving a plurality of wheels 41. The first drive units on each side of the chair are interconnected by a transverse extending power shaft assembly 19 powered by a motor 20 mounted below the seat 11. The motor carries a gear 21 on motor shaft 22, the gear driving an endless chain 23 passed around a gear 24 on a sleeve 25. The sleeve 25 contains bearings 26 therein to support a fulcrum shaft 27.

The lower sections 28 of the telescopic legs, have sleeve 25 mounted rotatably free therein. The upper section of the legs comprise a cylinder 29 receiving section 28 therein.

ice

A rod 30 secured to cylinder 29 and to the arm rest 13 supports a shaft 31 on which a hand wheel 32 is secured to rotate a gear 33 also secured on shaft 31. An endless chain 34 powered by gear 33 transmits manual power to a gear 35 secured on shaft 27. A clutch mechanism, not shown, disengages gear 35 from the shaft 27 when the chair is power driven; gear 35 being in driving engagement with shaft 27 only during manual operation. The ends of shaft 27 carry bevel gears 36 each of which is engaged with bevel gear 37 on a sleeve unit 38 for transmitting motion to a gear 39 to drive a gear 40 on wheel 41. Each wheel has an automatic clutch built in With a predetermined setting (not shown). The purpose of the automatic clutch mounted in each wheel is to automatically disengage the wheel from driving relationship with the gear 40 when the wheel contacts an obstacle, thus permitting the wheel to ride freely over the obstacle' After the wheel passes or overcomes the obstacle, the clutch automatically re-engages the drive gear 40.

As shown in FIGURES 1 and 2 a channel frame is provided on each side of the chair, the frame 50 being pivotable about shaft 27 between positions shown in FIGURE 7. Each channel frame 50 supports six wheel units 51, one of which is shown complete in FIGURE 2. Each wheel unit operates one wheel independent of the other wheels to climb or descend over a stair. Each wheel unit includes a housing unit 52 rigidly fixed on frame 50 which houses a square piston 53 that through a link 54 and collar 55 moves forwardly and rearwarrlly on the upper end of a pivotable bar 56 pivoted at its lower end on shaft 27 or one of the five corresponding shafts 27a, b, c, d and e. Control stops are provided for predetermined travel distance of the piston. In each wheel unit the sleeve unit 38 includes a retaining sleeve 57 on a ridge type barrel 58 comprised of a tubular pipe with key stock or ridge atfixed. Barrel 58 is set in ball bearings by means of set screws. A shaft 59 vertically movable with respect to the floor or surface on which the wheel is resting, holds wheel 41 on fixed alignment by means of a collar 66 at its upper end connected to a collar 61 on the bar 56.

The piston 53 has a sideward extending shaft 62 that extends out of slot 63 in the housing 52 and has a bevel gear 64 and sprocket 65 integrally aifixed together carried rotatably free on shaft 62. An endless chain 66 on each side of the chair transmits power between a spocket 65 and a sprocket 36 on each shaft 27, 27a, 11, c, d, and e. In this way the motor 22 drives all of the wheels 41 through the gears 21, 24 and chain 23 the main drive shaft 27 and gears 36 on either end thereof, and chains 66 at each side of the chair on gears 36 on each drive shaft 27, and 27ae, each drive shaft being in driving engagement with a pair of Wheels 41 on opposite sides of the chair.

Bevel gear 64 engages selectively gears 68 and 69. Gear 69 is freely rotatable on a stub shaft 70 supported on bracket '71. Gear 68 is rigidly fixed on worm 72 having disengage spring 73 at its lower end nested in a channel 74 of frame 50. The gears 68 and 69 provide forward and reverse transmission.

An arm 75 on worm 72 extends through an opening 76 in shaft 59. When the arm is fully up or down it is in a free position wherein rotation of the worm depresses the spring 73 which in turn lets a triggering unit engage a more solid object causing the arm to move into a free state. The spring overcomes the inertia state of the triggering unit at a determined moment which is when the worm rotation is changed. This action would now be a down thrust, or a rotation change would now mean a pull or retraction when driven to a predetermined extreme. The triggering units are conventional devices, such as ratchet gear mechanisms, adapted to engage and disengage as necessary. There are six triggering units on each side of the chair, and as will be seen later, these units operate only on descent of stairs and do not come into play when ascending stairs. Each triggering unit or ratchet device disengages its worm at the full travel positions of arm 75 at the top and bottom of the worm 72. Disengagement at the bottom of the worm 72 prevents locking or freezing up of the unit since all parts thereof, including the worm, barrel and wheels are rotating and thus prevents the downward driving force of the arm on the worm from damaging the apparatus. Disengagement of the worm 72 by the triggering device at the limit of travel of the arm 75 at the top of the worm, similarly prevents jamming or damage to the apparatus. At any particular time, the six triggering units on each side will be at different levels on their respective worms. When the first or sixth triggering units are at the top or bottom of their respective worms, the other triggering units will be at intermediate positions on their respective worms, but all worms will be disengaged.

The worm has also a disengage spring at the top that works the same as the lower spring. Its only purpose is to overcome inertia state, this being at moment of change of rotation as result of chair in motion the wheel hits an obstacle, namely steps of a stairway, resulting now in change of rotation of the worm.

The arm rests are each channel shaped on the underside wherein the top edge of a triangular plate 80 is slidable. Each plate 80 has a shaft 81 that travels in a slot 82 of an angle 83 secured to the frame 50. As the frame is tilted as shown in FIGURE 7 the shaft 81 travels from one end to the opposite end of slot 82. As shown in FIG. 1, frame 50 is pivoted on shaft 27 at one corner and the opposite end of the frame is tilted due to the inclination of the stairs; one or more sets of the wheels 41 being higher or lower than the similar wheels 41 associated with shaft 27.

A retainer plate 84 secured to one lower edge of the arm rest is secured to the cylinder section 29 of legs 14. A stabilizer 85 is in slide engagement with the rear side of plate 84, the stabilizer being secured to the frame 50. See FIG. 3.

A fiat stock bar 86 is supported on each frame 50 and has a two shift movement forward to engage piston 53 and gear 68 to retract legs. As best seen in FIG. 2, bar 86 is fixedly mounted in units 50 but slidably mounted in suitable mounting means (not shown) on frame 50. The bar 86 as thus mounted is capable of being moved forwards or backwards manually as shown by the arrows in FIG. 2. Shifting bar 86 forward places the apparatus in condition ascending. Shifting the bar 86 rearwardly places the apparatus in condition for descention.

As shown in FIGURE 1 a fiat stock stiffening plate 95 is provided on each side of the chair for maintaining shafts 31 at set distance from shaft 27. It will be noted that as the legs 14 are telescoped the rods 30 affixed thereto will slide in brackets 96 which support shafts 31.

In operative use when the chair travels along a level floor and subsequently encounters the first step of a stair for purpose of ascension, the automatic clutches on all wheels apply themselves momentarily as each wheel abutts with the obstacle or step causing rearward displacement of wheel 41 and causing the bar 56 to pivot forwardly about shaft 27 thus moving the piston 53 and causing power from gear 64 to he transferred to gear 69 thus causing reverse rotation of the worm 1 and ascension of arm 75 on the worm and raising the wheel so as to mount the step. Thus the remaining wheels remain on solid surface while a wheel is being retracted. When the chair attains the position shown in FIGURE 8 wherein the fourth wheel abutts the first step and the wheel is raised as above described and then the bar 56 pivots back to move the piston and change engagement of gear 64 to gear 68 to cause arm 75 to descend and cause a down thrust of the fourth wheel, an inclination occurs of the chair body respective to the drive mechanism 16 so that a person may sit at a normal angle while traveling on the stairway.

On descending stairs, when a wheel 41 leaves a stair, the weight of the chair and occupant is taken off the wheel, thus permitting the tension in the spring connecting member 56 to the bar 86 to become operative to pull the member 56 rearwardly. This operates member 54 and piston 53 to cause gears 68 and 69 to engage. Inasmuch as the reversible motor 20 is operated in the reverse direction when descending stairs, the engagement of gears 68-69 causes rotation of the worm 72 in the opposite direction from that in which it rotates on ascending stairs. Therefore, the wheel unit and wheel 41 is driven downwardly into engagement with the next lower stair.

It will be seen from the drawings and the above description of the various parts, that the apparatus comprises a chair having a motor 20 driving shafts 27, and 27a through e by means of an endless chain 23 and gears 21 and 24, and gears 36 and chains 66 as described previously. Auxiliary manual drive means is also provided on each side of the chair consisting of a hand wheel 32, shaft 31, gear 33, endless chain 34 and gear 35 aflixed to shaft 27. A frame on each side of the chair is pivotally mounted on shaft 27 for movement between horizontal and tilted positions as shown in FIGS. 1 and 7, respectively, a plate 84 afiixed to the chair body and a curved guide member 85 on the frame 50 serving to guide the tilting movement of the frame 58 as best seen in FIG. 3.

Six wheel units 51 are arranged in three pairs of such units on each side of the chair. Each of the wheel units 51 is rigidly mounted on a horizontal bar 86 on each side of the chair, the bar 86 being movably mounted on the frame 50 for movement between a forward position and a rearward position. Each of the wheel drive units 51 has a sprocket driven by an endless chain 66 and a sprocket 67 on one of the drive shafts 27, 27a, 27b, 270, etc. When the bar 86 is manually moved to its forward position bevel gears 64 on each of the sprockets 65 in the individual wheel units engages and drives a gear 68 to cause rotation of one of the worms 72 which operates as described hereinabove to drive mechanism rotating one of the wheels 41 of the wheelchair to permit the chair to ascend stairs. Similarly, manually moving the bar 86 on each side of the chair to its rearward position disengages gears 64 from gears 68 and engages them with reversing gears 69 causing the worms 72 to rotate in the opposite direction, to provide for descending stairs as described above.

I claim:

1. In a stair climbing and descending vehicle comprising a frame, means to support an occupant mounted on said frame, two sets of wheels mounted on said frame one set disposed on each of two opposite sides of said vehicle, a first drive shaft rotatably mounted on said frame, means for rotatably driving said first drive shaft, and means mounted on said first drive shaft for rotatably driving a first opposed pair of wheels consisting of the first wheel in each set of wheels on opposite sides of said vehicle, the improvement which comprises, a secondary drive shaft rotatably mounted on said frame for each additional opposed pair of wheels in said sets of wheels, sprocket and endless chain means connecting said first drive shaft and each secondary drive shaft whereby said secondary drive shafts are rotatably driven by said first drive shaft, means for raising each of said wheels substantially vertically and independently of the other wheels as said wheel encounters the riser of a stair on ascending stairs to elevate said wheel to the level of the next higher stair tread, and means for lowering each of said wheels substantially vertically and independently of the other wheels as said wheel leaves the tread of a stair on descending stairs to lower said wheel to the level of the next lower stair tread, whereby as said vehicle is propelled up and down stairs as the case may be, the wheels of each set of wheels are in contact with at least two stair treads at different levels.

2. A vehicle according to claim 1, including clutch means which automatically and separately disengage each wheel from driving relationship to said drive means as said wheel encounters a stair riser on ascending stairs and as said wheel leaves a stair tread on descending stairs, said means for driving said wheels remaining in driving engagement with those wheels resting on a stair tread while ascending and descending stairs.

3. A vehicle according to claim 2, wherein the means for driving said wheels comprises a reversible motor, whereby the direction of rotation of said drive shafts and said wheels may be reversed.

4. A vehicle according to claim 3, wherein said means for raising and lowering each of said wheels comprises a generally vertically disposed, telescopic wheel mounting unit carrying one of said wheels, said telescopic unit having outer and inner portions the oute portion determining the level of said wheel, said wheel mounting unit being mounted on said frame, an elongated vertically disposed worm rotatably mounted on said frame, a generally horizontally disposed arm, one end of said arm being connected to the outer portion of said telescopic wheel mounting unit, the other end of said arm being in threaded engagement with said worm, reversing gear means mounted on said worm, and means driven by said first and secondary drive shafts for rotatably driving said worm through said reversing gear means for rotation in a predetermined direction, whereby said arm travels along said worm thus raising and lowering the telescopic portion of the wheel unit and the attached Wheel, depending on the direction of rotation of the worm.

5. A vehicle according to claim 4, including means for shifting said means for driving said worm between a position in which said reversing gear means drives the worm in clockwise rotation and a second position in which said reversing gear means drives the worm in counter-clockwise rotation, thus providing for raising and lowering said wheels as desired.

6. A vehicle according to claim 5, including means at each end of said worm for temporarily disengaging said arm from threaded engagement with said worm and causing a change in the direction of rotation of said worm be fore re-engagement of said arm therewith,

7. A vehicle according to claim 6, including means for pivoting said frame about the axis of said first drive shaft and with respect to said means for supporting an occupant, to permit said frame to assume a position generally parallel to the incline of stairs on ascending and descending such stairs, but to maintain said occupant supporting means generally horizontal.

References Cited UNITED STATES PATENTS 3,049,364 8/1962 Clay 2805.26 X 3,166,138 1/1965 Dunn ISO-9.24 3,241,848 3/1966 Flory 2805.26

FOREIGN PATENTS 932,361 11/1947 France.

LEO FRIAGLIA, Primary Examiner.

US Cl. X.R. 8 

